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23 Caffeine Drug Interactions You Need to Know

woman holding a combination of medicines and vitamins in her left hand and coffee in a cup in her right hand

If you are a coffee lover who also needs to take various medications or you know someone who does, it’s important to know which medications caffeine can interact with, so you don’t encounter any surprise health issues. Interactions between medications can be extremely dangerous, so it’s better to be safe than sorry. Keep reading as we go over several popular drugs that can interact with caffeine.

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The 23 Caffeine Drug Interactions:

1. Cocaine

  • Effects: Irregular heartbeat

While cocaine is illegal in most parts of the world, it’s worth mentioning here because its severe interaction with caffeine can cause an irregular heartbeat, possibly leading to a life-threatening situation.


2. Esketamine

  • Effects: Significant increase in blood pressure

Esketamine can have a big interaction with caffeine, and consuming the two simultaneously could lead to a significant increase in blood pressure. Before taking this drug, it’s important to let your doctor know if you regularly consume caffeine.


3. Tizanidine

Sirdalud
Image Credit: Sirdalud, Wedson, Wikimedia Commons CC 3.0 Unported
  • Effects: Extreme loss in blood pressure

Consuming tizanidine and caffeine together can cause an extreme reaction in which the blood pressure drops rapidly, especially when rising from a sitting position. This can cause a person to become dizzy and fall over, possibly causing injury. Tizanidine, esketamine, and cocaine are the drugs with the biggest reactions to caffeine.


4. Abametapir Topical

  • Effects: Increased blood levels

Consuming abametapir topical along with caffeine can increase your blood levels. It can also increase the effects of caffeine, causing nervousness.


5. Adenosine

  • Effects: Decreases the effectiveness of adenosine

Consuming caffeine while taking adenosine can decrease the strength of the drug, making it less effective.


6. Alosetron

  • Effects: Potentially serious gastrointestinal side effects

Consuming caffeine while you are taking alosetron can result in potentially serious gastrointestinal side effects that can be quite painful and require a visit to the hospital. It can also increase your blood levels of alosetron, requiring doctors to adjust your dosage.


7. Anagrelide

  • Effects: Affects blood levels of the drug

Consuming caffeine while taking anagrelide can increase how much of the drug is in your system, requiring an adjustment to your dosage. It can also increase caffeine’s effects, leading to nervousness or sleeplessness.


8. Bendamustine

  • Effects: Affects bone marrow function

Consuming caffeine while taking bendamustine can result in more of the drug being present in the bloodstream, which can affect bone marrow function. You may also notice paleness, fatigue, and dizziness when consuming both simultaneously, which will indicate that it’s time to call the doctor.


9. Capmatinib

  • Effects: Increases the effects of caffeine

Consuming capmatinib and caffeine can boost the caffeine’s effects, leading to dizziness, nervousness, and difficulty sleeping. It can also boost the amount of capmatinib in the bloodstream.


10. Ciprofloxacin

  • Effects: Increases the effects of caffeine

Ciprofloxacin will significantly boost caffeine effects if you drink it while you’re on the drug. Many people complain of nervousness, dizziness, difficulty sleeping, and increased blood pressure when trying to take both.


11. Cycloserine

  • Effects: Affects the central nervous system

If you consume caffeine while taking cycloserine, it can have serious effects on your central nervous system, resulting in symptoms similar to a caffeine overdose, like nervousness, tremors, and even psychosis. If you notice any of these symptoms when taking cycloserine, we recommend calling a doctor immediately.


12. Deferasirox

  • Effects: Increases the effects of caffeine

Deferasirox is a drug that can become more plentiful in the bloodstream if you consume caffeine while you’re taking it. It can also boost the effects of caffeine, causing nervousness.


13. Dipyridamole

  • Effects: Increases strength of the drug

Consuming caffeine and dipyridamole can increase the effects of the drug, making it potentially dangerous. Most experts recommend that you stop consuming caffeine 12 to 24 hours before taking dipyridamole.


14. Duloxetine

  • Effects: Increases the amount and strength of the drug

Consuming caffeine and duloxetine is dangerous because it causes more of the drug to be present in your bloodstream and increases its potency.


15. Echinacea

  • Effects: Increases the effects of caffeine

Consuming Echinacea and caffeine can increase the effects of the caffeine, causing nervousness and sleeplessness. It can also increase your blood pressure.


16. Enoxacin

  • Effects: Increases the effects of caffeine

Enoxacin is a drug that will increase the effects of caffeine if you consume it at the same time. When combining these two drugs, some people report headaches, dizziness, and even nausea.


17. Fexinidazole

  • Effects: Increases the amount of the drug in your system

Consuming fexinidazole and caffeine increases the amount of fexinidazole in your system, possibly leading to side effects that will require a dosage adjustment.


18. Fluvoxamine

  • Effects: Increases the effects of caffeine

Fluvoxamine can increase the effects of caffeine to the point where many people experience vomiting, headache, dizziness, nervousness, and high blood pressure. Most experts highly recommend that you avoid caffeine while taking this drug.


19. Givosiran

  • Effects: Increases the effects of caffeine

Givosiran is a drug that can boost the effects of caffeine while you’re taking it. While symptoms seem to be less dramatic than several other drugs on this list, it’s best to avoid consuming caffeine when possible, to avoid problems.


20. Hydroxyprogesterone

  • Effects: Reduces the amount of the drug in the bloodstream

If you consume caffeine while taking hydroxyprogesterone, the interaction between the two can reduce the amount of the drug in your bloodstream, causing it to be less effective and requiring a dosage adjustment.


21. Lithium

  • Effects: Increases the effects of caffeine

Consuming lithium and caffeine together can result in a stronger reaction to the caffeine. If you consume a large amount, it can lead to nervousness and even vomiting.


22. Methotrexate

  • Effects: Reduces the effectiveness of the drug

Consuming caffeine while taking methotrexate can work to reduce the drug’s effectiveness. Since it is primarily used to treat arthritis, caffeine consumption can cause increased pain.


23. Viloxazine

  • Effects: Increases the effects of caffeine

Consuming caffeine while you are taking the medication viloxazine can result in you feeling increased effects of the caffeine. Many people complain of nausea, vomiting, headache, tremors, nervousness, and difficulty sleeping when combining these two drugs.

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What Are the Most Common Interactions Between Drugs and Caffeine?

There is a wide variety of interactions that can occur between medications, and it’s never a good idea to take any risks without talking to your doctor first. On this list, an increase in the effects of caffeine is quite common. This increase can be hardly noticeable or leave you nauseated and vomiting. It’s also common for the interaction to cause more or less of the drug to be present in the bloodstream. Having too little of the drug in your system can cause it to be less effective, while too much will usually result in health risks.

man and woman having coffee outside their house
Image Credit: Greta Hoffman, Pexels

How Do I Know If Caffeine Will Interact With the Drugs I’m Taking?

The best way to find out if caffeine will interact with any drugs is to carefully read the documentation that comes with your medication. Your doctor or pharmacist should also be able to tell you if your morning coffee will interfere with your prescription.

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Conclusion

We highly recommend asking your doctor about each of the drugs that you need to take to determine if there are any concerns about caffeine. You can find caffeine in many foods and beverages, so knowing that you need to avoid it can be vital. While many of the interactions on this list may seem minor, it’s still not worth the risk. Esketamine and tizanidine in particular will have a big reaction to caffeine, so you will need to avoid caffeine completely when taking these.


Featured Image Credit: kamir_vp, Shutterstock

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Ed Malaker

Ed Malaker, a veteran writer, has contributed to a wide range of blogs that cover tools, pets, guitars, fitness, and computer programming, and of course, coffee. He drinks a lot of it when he writes, making him an expert indeed. When he’s not writing, Ed is usually performing DIY projects around the house or working in the garden. He’s also a musician and spends a lot of time helping people fix their guitars and composing music for independent films.

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